WO2008082320A1

WO2008082320A1 - Bicycle rim with wear indicator

Info

Publication number: WO2008082320A1
Application number: PCT/PT2007/000001
Authority: WO
Inventors: Armando Levi Silva
Original assignee: Rodi-Metalúrgicas Do Eixo, S.A.
Priority date: 2007-01-05
Filing date: 2007-01-05
Publication date: 2008-07-10
Also published as: EP2114695A1

Abstract

The present invention relates to a bicycle rim with wear indicator in frictional contact with a brake pad. It is essentially characterised in that small indents with different depths are placed along its sidewalls, where the brake pads apply their braking action when they are pressed against the surface of the aforesaid sidewalls, thus making it possible for the cyclist to visualise the durability of the rim.

Description

DESCRIPTION

"BICYCLE RIM WITH WEAR INDICATOR"

Field of the invention

The present invention relates to a bicycle rim with a wear indicator, specifically a bicycle rim which comprises, along the sidewalls in contact with the brake pads, wear indicators, which make it possible for the cyclist to visualise the durability of the rim and consequently the safety thereof.

Wear indicators placed on bicycle rims are important to make it possible to know how far a rim meets the conditions necessary for being safely used. Particularly as regards those known as all terrain bicycles, it is essential to use the material in perfect safety conditions. In fact, a bicycle of this type is subject to great strain, usually with constant use of the brake system, which wears the rim and renders it more fragile due to the reduction in the thickness of its walls.

Prior art

Several systems are known which indicate the wear of bicycle rims. Among them are those indicated in documents US6418873 and US2001028192.

Patent US6418873 relates to a bicycle wheel rim which includes an annular rim body which includes left and right sidewalls spaced apart from each other. Each of the sidewalls has a radial inner edge proximate to the central axis, a radial outer edge distal to the central axis, and a lateral outer brake pad contacting surface opposite to the other one of the sidewalls. The annular rim body further includes an annular base wall interconnecting the radial inner edges of the left and right side walls. The brake pad contacting surface of each of the sidewalls is formed with a wear- indicating projection adapted to be in frictional contact with a brake pad. The wear-indicating projection is formed as a continuous annular projection that extends along a respective one of the side walls. The brake pad contacting surface gradually wears out during use of the bicycle wheel rim to eventually render the wear-indicating projection to wear off, thereby indicating that wearing of the bicycle wheel rim to a predetermined extent has occurred.

Patent US2001028192 relates to a bicycle wheel rim provided with a wear indicator. The bicycle wheel rim has an outer annular portion, an annular spoke attachment portion and a pair of oppositely facing annular braking surfaces. The outer annular portion is adapted to receive a tire and the annular spoke attachment portion is coupled to the outer annular portion. The annular spoke attachment portion is adapted to be coupled to a plurality of spokes. At least one of the annular braking surfaces has a wear indicator consisting of a recess.

The wear indicators of this invention have characteristics different from those of the prior art, as will be described hereinafter.

Summary of the invention

The objective of the present invention is to design a bicycle rim which indicates to its user, in a clear way, the wear of the rim, thus enabling him to use it always in safe conditions. Besides this, it has great advantages in relation to the rims equipped with wear indicators known in the prior art .

In fact, the simple fact of not imparting the sidewalls and braking surfaces of the rim with projections or recesses, but rather providing three circular indents with different depths, makes it possible:

- to indicate the wear status of the rim over the time through three levels of wear;

- to enable the user to foresee the replacement of the rim as from the moment when the intermediate indent, which constitutes the mean lifetime of the rim, is worn; - to prevent the body of the rim from weakening; and

- to easily obtain the said indents, i.e. the rim will merely be subject to a simple and economical machining process, using a milling cutter of a predetermined diameter.

Brief description of the drawing

The following description makes reference, for the purpose of clarity of presentation, to the single drawing attached hereto, without any restrictive character, which shows the surface of the bicycle rim equipped with the wear indicators .

Detailed description of the invention

As can be observed, indicators 1 formed by indents are placed diagonally on a part of the rim 2 which corresponds to the braking surface 3. The indents of the indicators 1 are made with a 2 mm diameter milling cutter and have three different depths. Preferably, these depths are 0.5 mm, 0.6 mm and 0.7 mm. As is easily understood, wear is caused by the brake pads on the sidewalls of the rim which correspond to the braking areas.

The meaning of each of the indicators is the following: - when the three points are visible, corresponding to the same number of indents, the rim is in perfect conditions to be used with maximum safety.

- when only two points are visible, corresponding to the same number of indents, i.e. one of the indents is no longer visible due to the wear suffered, which corresponds to a 0.5 mm thickness, the rim is still safe to use but has reached its mean lifetime, making it possible for the user to foresee its replacement;

- when only one point is visible, corresponding to one indent, i.e. the rim has suffered a wear of 0.6 mm thickness, which corresponds to the depth of the second indent, this means that the rim must be replaced shortly; and

- when no point corresponding to any of the indents can be seen, the rim has suffered wear along all its perimeter of a thickness corresponding to that of the indent, i.e. 0.7 mm, being therefore too weak to be subjected to the strain for which it was designed, and must be replaced, given that its use no longer guarantees the necessary safety.

There is a 0.1 mm difference in thickness between each point corresponding to the aforesaid indents and, according to previous calculations and studies, the rim covered an average distance of between 2,000 and 3,000 km. Preferably, the three points of the wear indicators 1 are placed on both sidewalls and braking surfaces of the rim. This will also make it possible to verify the braking balance, given that a difference in wear between the two surfaces means a different pressure and a corresponding different friction of the brake pads against the rim.

As will be obvious to those skilled in the art, other alterations are possible. For example, a different indent system can be designed, with more or fewer indents than those mentioned hereinabove, having depths that can also be different. These and other alterations must be considered as falling within the scope of the following claims .

Claims

1. Bicycle rim with wear indicator in frictional contact with a brake pad, characterised in that small indents with different depths are placed along its sidewalls, where the brake pads apply their braking action when they are pressed against the surface of the aforesaid sidewalls, thus making it possible for the cyclist to visualise the durability of the rim.

2. Bicycle rim with wear indicator in accordance with the preceding claim, characterised in that the rim is in perfect safety conditions while it is possible to visualise the three indents and in that when it is not possible to visualise any indent, this means that the rim has suffered wear along the sidewalls which advise its replacement, the failure to visualise one or two indents indicating the average lifetime of the said rim.

3. Bicycle rim with wear indicator in accordance with the preceding claims, characterised in that the aforesaid three indents are placed diagonally on the sidewall of the rim and have depths of 0.5 mm, 0.6 mm and 0.7 mm.

4. Bicycle rim with wear indicator in accordance with the preceding claims, characterised in that the distance between each of the indents placed diagonally is established so that they will be covered by the brake pad.

5. Bicycle rim with wear indicator in accordance with the preceding claims, characterised in that the indents are made using a 2 mm diameter milling cutter.